Traditionally, the polyester repair markets have utilized well-defined processes in the area of damage repair. Unsaturated polyester resins, primers, fillers, adhesives, or putties are used to resurface and reshape damaged areas. For ease of understanding, the term “resin” will be used in the following description; however, it is to be understood that the term includes cured resins and prepolymers (uncured resins), primers, fillers, adhesives, and putties. The method for catalyzation and application of the resin is as much an art as it is a science. This is due in part to the very small amount of peroxide hardener (catalyst) that is used to cure the much larger amounts of unsaturated polyester resin properly. The optimum peroxide level needed to cure the resin is generally about 1 to 3 parts per hundred of the resin by weight. The resin and peroxide are packaged in separate containers, typically a large can for the filler (8 oz. to 55 gal.), and a small tube for the peroxide catalyst (0.25 oz. to 4 oz.).
The user dispenses a variable amount of resin into a cup or onto a mixing board, and adds the peroxide catalyst, essentially guessing at the correct amount for proper catalyzation. The consequences of improper catalyzation of the resin include loss of adhesion to the substrate, uncured surface (tacky), cracking of the resin due to excessive heat generation, migration of uncured resin organics to subsequent coatings resulting in discoloration of top coats, outgassing of uncured material in the presence of ultraviolet or heat energy from sunlight or paint baking systems resulting in blistering and other damage to the topcoat, as well as other problems that may require removal and replacement of the repair.
As a result, efforts have been made to control metering of the organic peroxide to ensure that the proper amount is mixed with the thermoset resin. Due to the nature of many of the commercially available peroxide solutions, which have a viscosity similar to water, dispensing in a mechanical metering system was difficult in non-spray applications. One attempt to solve this problem is described in U.S. Pat. No. 5,880,181, which disclosed organic peroxides in combination with a cellulose ester as a thickening agent, and a fumed silica and/or a hydrogenated castor oil as a thixotropic agent to form a thicker form of the organic peroxide.
There remains a need in the art for a more volumetrically controllable form of the organic peroxide.